It is known an information recording medium cartridge as shown, for example, in FIG. 24.
The information recording medium cartridge (refer hereafter to as “cartridge” simply) 101 is provided with an information recording medium (refer hereafter to as “disc”) 102, such as optical disc, magneto-optical disc or the like, having recording layers arranged on right and reverse sides, a cartridge casing (refer hereafter to as “shell”) 103 which rotatably stores the disc 102, and a shutter 105 slidably mounted to the shell 103 for opening and closing recording and/or reproducing openings (refer hereafter to as “openings” simply) arranged in right and reverse sides of the shell 103.
The shutter 105 is provided with a first shutter plate 106 which opens and closes an opening 104 on the right side of the shell 103 and a second shutter plate 107 which opens and closes the opening 104 on the reverse side of the shell 103. The shutter 105 is formed roughly like an U shape by bending a metal plate to simultaneously open and close the openings 104 on the right and reverse sides of the shell 103.
When loading the cartridge 101 into a recording and/or reproducing device (refer hereafter to as “drive unit”), the shutter 105 is driven and operated by a shutter operating member mounted to the drive unit to simultaneously open the openings 104 on the right and reverse sides of the shell 103.
With the cartridge 101, as shown in FIG. 25, the disc 102 is chucked on a turntable 301 of the drive unit through the opening 104 on the reverse side of the shell 103 for rotation and driving, and recording and/or reproducing of the disc 102 is carried out by an optical pickup 302 through the opening 104 on the reverse side.
With the conventional disc 101 using the shutter 105 having first and second shutter plates 106, 107 integrally formed, when opening the opening 104 on the reverse side of the shell 103 for recording and/or reproducing, the opening 104 on the reverse side of the shell 103 is also opened even when there is no direct relation directly with recording and/or reproducing, raising an inconvenience that dust 303 or the like entering the shell 103 through the opening 104 on the right side adheres and deposits on the top surface of the disc 102. Adhesion of the dust or the like has a considerable adverse influence on a high-density large-capacity disc.
In order to solve the above inconvenience, a cartridge 201 using a divided shutter as shown in FIGS. 26 and 27 has been developed. In the cartridge 201, a shutter 205 comprises a first shutter plate 206 which opens and closes an opening 204 on the right side of a shell 203 and a second shutter plate 207 which opens and closes an opening 204 on the reverse side of the shell 203. The first and second shutter plates 206, 207 are moved individually to open and close the openings 204 independently.
The first and second shutter plates 206, 207 are provided with a closing portion 208 which closes the opening 204 and an open portion (recessed window) 209 continuously arranged with one side of the closing portion 208 to open the opening 204.
As shown in FIG. 26, when the first and second shutter plates 206, 207 are in a first position, the closing portions 208 of the first and second shutter plates 206, 207 are in the overlapped state to close the openings 204 arranged in right and reverse sides of the shell 203. And when being moved to a second position as shown in FIG. 27, the open portion (recessed window) 209 and the openings 204 are overlapped one another, opening the openings 204.
As shown in FIG. 28, the first and second shutter plates 206, 207 are mounted to a slide member 210. The slide member 210 is divided into a first slide portion 211 to which the first shutter plate 206 is mounted and a second slide portion 212 to which the second shutter plate 207 is mounted.
When loading the cartridge 201 using the divided shutter into the drive unit, only the second shutter plate 207 is driven and operated by a shutter opening member mounted to the drive unit to open only the opening 204 on the reverse side of the shell 203. And as shown in FIG. 29, through the opening 204 on the reverse side of the shell 203, the disc 202 is chucked on the turntable 301 of the drive unit for rotation and driving, and recording and/or reproducing of the disc 202 is carried out by the optical pickup 302. On the other hand, the first shutter plate 206 closes the opening 204 on the right side of the shell 203 to prevent an intrusion of dust 303 or the like into the shell 203 through the opening 204.
The conventional cartridge 201 using divided shutter raised the following problems:
(1) As shown in FIG. 26, since the first and second shutter plates 206, 207 are provided with closing portion 208 which closes the opening 204 and open portion (recessed window) 209 which opens the opening 204, a width W1 in the moving direction becomes large (the width W1 of the first and second shutter plates 206, 207 is equal to a value obtained by adding a width W2 of the closing portion 208 to a width W3 of the open portion 209). Therefore, the first and second shutter plates 206, 207 become larger and heavier by that amount. Moreover, the cost of the first and second shutter plates 206, 207 becomes higher.
(2) In order to put the closing condition of the opening 204 of the shell 203 as shown in FIG. 26 to the opening condition of the opening 204 as shown in FIG. 27, the first and second shutter plates 206, 207 should be moved by roughly the same width W4 as the width W2 of the closing portion 208. Therefore, a width W5 of a moving area of the first and second shutter plates 206, 207 for opening and closing the openings 204 is equal to a value obtained by adding the width W1 of the first and second shutter plates 206, 207 to the moving width W4, which is a value roughly equal to a width W6 of the shell 203, thus leading to difficult arrangement of a label adhesion area for an index card or the like.
(3) The first and second slide portions 211, 212 are formed by simply vertically dividing into two parts the slide member 210 in the moving direction, so that, as shown in FIG. 30, for example, the first and second slide portions 211, 212 are inclined to separate the first and second shutter plates 206, 207 from the right and reverse sides 203a, 203b of the shell 203, producing a clearance G between the first and second shutter plates 206, 207 and the right and reverse sides 203a, 203b of the shell 203, thus becoming a cause of intrusion of dust.
An object of the present invention is to allow arrangement of a label adhesion area for an index card or the like on one side portion of the openings of the cartridge casing by reducing the width of the first and second shutter plates in the moving direction. Further, it is to achieve a reduction in the weight and cost of the first and second shutter plates.
Another object of the present invention is to facilitate handling of the first and second slide members and its assembling to the cartridge casing by integrally coupling them by a spring member.
Still another object of the present invention is to prevent the first and second shutter plates from being separated from the right and reverse sides of the cartridge casing by inclination of the first and second slide portions.